Known embodiments of lining panels for the lining of fuselage cells of aircraft, and in particular for use in propeller-powered aeroplanes, must meet a large number of requirements.
Firstly, the lining panels must have adequate sound permeability. Furthermore, the lining panels should provide adequate electromagnetic shielding in case the electrical lines within the aircraft do not have adequate shielding. In addition, the lining panels must be adequately isolated from deformations of the fuselage cell, because insufficiently elastic fastening of the panels forming the lining to the fuselage cell causes stresses. The lining panels themselves only withstand a pressure difference of up to 80 hPa. In the case of a sudden drop in pressure in the interior space of the fuselage cell, furthermore, a pressure equalization must be possible through the lining without the panels intruding into the passenger compartment and possibly injuring the passengers. Finally, the lining is also intended to allow adequate compensation for production tolerances.
Lining panels of this type are produced by sandwich panels, which have, for example, a honeycomb core with outer layers applied to both sides. The outer layers are formed with preference by a fibre reinforced thermosetting polymer material, which is provided at least in certain regions with a metal backing, to achieve an adequate electromagnetic shielding effect with at the same time adequate sound permeability. The lining panels are usually connected to profiles, which are in turn connected to the fuselage cell by means of mounts. The profiles, arranged with preference in the manner of a truss, form what is known as the “lining framework”. The pressure tight sealing between the lining panels and the profiles is performed by peripheral seals. The required pressure equalization between the interior space of the fuselage cell and the intermediate space located between the lining and the outer skin of the fuselage cell takes place in the case of a sudden drop in pressure in the interior space of the fuselage cell (known as “rapid decompression”) through additional ventilation flaps in the lining.